As a practical matter, in the USA and Canada the majority of residential, commercial, and industrial electrical wire connections need to be made using connectors certified to the Underwriters Laboratories UL 486A-486B wire connector standard of testing (in Canada the same harmonized standard is named C22.2 No. 65), in order to comply with the NEC (National Electrical Code) and other NFPA (National Fire Protection Association) and other applicable safety codes. An electrical current carrying wire (or “conductor”) terminal connector that is not already appropriately tested and certified by the appropriate NRTL (National Recognized Testing Laboratory) for connecting a particular wire type is of little commercial value, is potentially unsafe, and commonly voids fire insurance policies due to risk.
When connecting certain stranded or flexible copper stranded wire in mechanical screw compression wire connectors, users are frequently required by electrical and fire safety codes and/or customer specification or preferences, to use a copper ferrules (a thin wall tubular copper sleeve with a flared mouth for ease of wire insertion) to protect the fragile wire strands from damage by the wire compression screw. Also, the ferrule is useful as an orderly means of controlling the fine strands of stranded or flexible wire during insertion into a connector. These standard marketplace ferrules, by convention, and past practice, are crimped onto the wire first, using specified crimping tools and dies, before being finally and additionally clamped inside the wire connector itself. That wire and ferrule crimping procedure is also subject to certification under UL486A-B/C22.2 No. 65 or UL486F for the joint to have broad commercial use in Listed wire connectors. In spite of this additional ferrule-to-wire-crimp testing work, the certified wire and crimped ferrule combination is still not generally permitted to be used in a standard wire connector until the ferrule and wire combination has been tested a second time as a crimped ferrule wire assembly.
Standard “generic” DIN46228 part 1 and part 4 ferrules that have been further tested using UL486F or UL486A/C22.2 No. 65 for crimping using special crimping tools the many different wire sizes and stranding types, typically have a premium cost, and less commonplace than generic standard DIN 46228 ferrules. Mass produced generic ferrules are not burdened with the testing cost and therefore are relatively more economic. The standard generic ferrules are made to the same construction requirements originally defined in DIN standard 46228 parts 1 and 4.
The difference is mainly that of pre-testing, packing and labeling with the rated wire and ferrule combinations.
The purchase of specially assigned ferrule crimping tools and dies for UL certified ferrules increases the user cost further and can be very inconvenient since they must be acquired before the wire connection can be made.
Prior devices show a long standing use of built-in component ferrule, OEM custom design (custom non-standard ferrules and which cannot be used without the ferrule), having a single sized ferrule for all wires in the entire connector range, which does serve to eliminate the pre-crimping of the wire and therefore also eliminates certified crimping tools from the user requirements. However, the connector has to be covered in insulation in order to have a means to retain the custom ferrule component, making it expensive. Additionally, and crucially, the Dual Rated certification is lost, since the integrated, and always required and supplied copper ferrule does not support UL486B/C22.2 No. 65 aluminum wire ratings. The single maximally sized, specially dimensioned OEM ferrule, integrated into previous connectors, does not solve the need for a single connector that can utilize ferrules on copper wire, only when needed, still without special crimping tools, and at the same time, be certified to connect all forms of common NEC code wire including aluminum wire, retaining the connector's Dual Rated certification for both copper and aluminum conductors.
The mainstream approach which maintains the Dual Ratings for aluminum and copper wire requires that ferrules be previously pre-crimp certified for use with the stranded copper wire being used and additionally, certified again in the wire connector as a pre-crimped ferruled wire, further clamped by the connector clamping screw. This is a duplication of testing and, in every single use of the ferrule, a duplication of the crimping method labor costs.
Therefore, a need exists for novel electrical coupling methods for forming electrical connections. A further need exists for novel electrical coupling methods which form electrical connections that are certified to connect all forms of common NEC code wire including aluminum wire, retaining the connector's Dual Rated certification for both copper and aluminum conductors. There is also a need for novel electrical coupling methods which form electrical connections without the need for special crimping tools and their associated tooling, labor, and time costs.